Automatic combined heating and compressing apparatus



Feb. 17, 1942.

G. s. VARCOE ETAL,

AUTOMATIC COMBINED HEATING AND COMPRESSING APPARATUS Filed Sept. 1.0[1938 GARLAND 6'. 1479605 [am/v A. P000) Arr-01m n:

Patented Feb. 17,1942

AUTOMATIC COMBINED HEATING AND COMPRESSIN G APPARATUS Garland s. vmoe, Cleveland Heights, and Edwin A. Purely, University Heights, Ohio, assignors to Garland S. Varcoe, Cleveland Heights, Ohio Application September 10, 1938, Serial No. 229,314 Claims. c|. 18-17) This invention, as indicated, relates to an automatic combined heating and compressing apparatus. More particularly, it comprises an apparatus to subject material placed therein to predetermined conditions of pressure and temperature. The apparatus is of particular utility in connection with the closing of dental flasks having therein synthetic material, such as Bakelite, preliminary to the curing steps in the production of such plastic structures.

Heretofore it has been the practice in various lines of manufacture, and particularly in dental laboratory procedure, where pressure was to be applied progressively in connection with certain temperature conditions, to apply such pressure manually after checking the temperature of the material in the course of processing. Such manual adjustment has involved lack of uniformity of control and is not conducive to precision or to the attainment of dependable and uniform results in the product resulting from the operation.

The principal object of the invention is to provide an apparatus for progressively applying pressure to material to be conditoned under cer tain predetermined amounts of heat and pressure over a fixed period. 7

Another object of the invention is to provide an apparatus adapted to apply heat to material to be subjected to pressure and maintain such heat at a predetermined amount together with the application of pressure to such material progressively over a predetermined length of time to attain certain uniform characteristics in the material undergoing treatment.

Another object of the' invention is to provide a press adapted to operate upon one or more material supporting elements to maintain heat within range of a predetermined amount and to progressively apply pressure thereto uniformly over a period of time so as to produce certain predetermined characteristics in the material undergoing treatment.

Another object of the invention is to provide a press having one or more movable platens and a fixed abutment with means for heating one or more of said platens and imparting such heat to the material undergoing treatmentand means for progressively moving one or more of said platens so as to appply pressure thereto progressively over a predetermined range of movement.

Another object of the invention is to provide a press having one or more movable platens and a fixed abutment for receivingmaterial to be treated and moving said platen or platens at a predetermined rate of movement so as to apply pressure to the material being treated progressively with means for discontinuing such pressure at a predetermined point and with means additional to the pressure applying means for releasing the pressure after a predetermined limit has been reached.

Another object of the invention is to provide a press with transmission and motor assembly and switch control for said motor, such switch being adjustable for actuation at a predetermined point of motion of said press and operating with means for releasing said press independently of said pressure applying means.

Other and further objects of the invention will appear in the course of the following description. To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims, the annexed drawing and the following description setting forth in detail certain mechanism embodying the inventions, such disclosed means constituting, however, but several of various forms in which the principle of the invention may be used.

In said annexed drawing:

Fig. 1 is a side elevation partly in section showing an apparatus embodying the principles of the invention, as seen along the lines l-l indicated in Fig. 2; a

Fig. 2 is a fragmentary plan view partly in section, as seen along th lines 22 looking in the direction of the arrows; and

Fig. 3 is a fragmentary front elevation of the switch mechanism, as seen along the lines 3-3 shown in Fig. 1 looking in the direction of the arrows.-

As is clearly shown in Fig. 1, the apparatus comprises a base plate I upon which is supported a press structure 2, a transmission 3 and a motor 4, the parts being so related to each other as to.

transmit power from the motor to the press at a very low ratio to the end that a very slow but uniform rate of movement will be transmitted to the movable members of the press. The press may assume various forms, but in the structure illustrated comprises a frame with four equally spaced standards 5, said standards being of larger diameter over their lower range of extent and having shoulders 6 at their upper ends serving as limit stops for the lowermost platen or movable abutment I which is engaged upon intermediate portions 8 of the standard of plate being held in position by means of nuts I5 engaged over screw-threaded terminal portions l6 at the upper ends of the standards.

While two platens have been shown in Fig. 1 it is to be noted that the uppermost platen shown may be omitted, or that a series of upper platens similar to the platen or movable abutment I may be provided at the upper portion of the press in accordance with the requirements of the work in hand. Where two movable platens are provided as shown in Fig. 1 when but a single space of the press is required for the material, in this instance a dental flask l1, the upper space may be provided with a pressure distributor element l8 in the form of a steel tubular member of a size to approximately fill the area between the standards of the press and distribute the pressure adjacent the margins of the uppermost platen and the fixed abutment of the press.

The standards, in place of being provided with shoulders at intervals to serve as spacing or limit stops for the platens, could be made of uniform diameter throughout and be provided with collars or other means for spacing the movable-elements engaged uponsuch standards.

In theapparatus shown each of the platens or movable abutments 1 and H is provided with a heatingelement 2| in the form of an annular coil of suitable resistance material 22 engaged .within suitable insulating material 23. The circuit connections 24 for the coils are suitably insulated by means of nipples 25 from contact with the platens and may each be provided with suitable thermostats for maintaining uniform heat in each of the respective platens. Such thermostats may be adjustable'so that any required degree of heat may be provided for the type of material undergoing modification.

I The upper platen or movable abutment II has a plane upper and lower face while the lowermost platen is provided with a plane surface on its upper side and has centrally of its under side a boss 26 countersunk to provide a socket 21 to receive the shaft 28 of the press, and also countersunk to provide a recess 29 to receive the upper end of a coil spring 3|. The coil spring is housed within a recess 32 provided in the upper end of the shaft 28, and is normally of a length and of a stiffness to hold the lowermost platen or movable abutment 1 in slightly spaced relation to the upper end of the shaft 28, but is responsive to the to move further into the recess in the boss 26.

This relative movement of the shaft to the lowermost platen is sufficient in degree to operate the switch controlling mechanism as will be hereinafter described. The shaft 28, it will be noted, isv

formed with an enlarged cylindrical upper portion terminating in a conical section 33 serving as a hub for an adjusting wheel 34 frictionally engaged thereover and also locked thereto by means of a set-screw 35 extending at an angle through a socket 36 in the hub of said adjusting wheel 34 provided with four spokes 31 which are to the underside of the platen or movable abutment 1.

The means for applying pressure to the apparatus through the under side of the lower platen or movable abutment 1 will now be described.

- The shaft 28, when locked against rotation by the locking bar 38 carried on the adjusting wheel 34, which in turn is non-rotatably fixed to the shaft, is free to slide vertically up or down. The means for bringing about vertical movement of the shaft 28 comprises a gear driven collar 4| having an internally threaded central aperture 42 engaging a screw-threaded section 43 at the lower end of the shaft. The lower end of the shaft is of reduced diameter, and is provided with an axial bore 44 extending. from its lower end partly into the tapered section 33 heretofore referred to. The collar 4| has a disk like extension 45, carrying bevel gear teeth 46 on its under mar ginal area, such teethmeshing with a drive pinion 41 on the drive shaft 48 projecting from the transmission unit 3 heretofore referred to, such unit in turn being connected with the power input shaft 49 of the unit having a pulley 5| with a belt drive 52 from a pulley 53 on the shaft 54 of the electric motor 4 which may be supported on the base by a bracket 55.

The collar 4| and its disk extension 45 is rotatably supported on a central tubular member 6| firmly secured to the base intermediate the standards 5 heretofore described. A thrust ball bearing assembly 62 is interposed between the base 63 on the underside of the collar and the upper end of the tubular member 6|. Centrally of the tubular member 6| a guide pin 64 is mounted, said pin slidingly engaging within the bore 44 of the shaft 28 and extending to a point terminals of the circuit conductors 12, 13 within one end of the same adapted to be closed or connected by a globule of mercury 14 when in normal position, and to be opened whentilted as shown in Fig. 3.

The tubular element 1| is supported in a clamping member or frame 15, pivotally mounted on pin 16, carried by a supporting plate 11. The supporting plate at its upper end is provided with a pair of elongated slots 18, through which are engaged adjusting screws 19 received in screwthreaded openings in the outer face of the lower platen I, thus permitting a shift in the position of the plate to any extent required in setting up the apparatus for any particular work. The lower portion of the plate 11 is bent to form a lower edge 8| of rectangular cross-section and is provided with alined openings 82. 83, to receive a switch actuating pin 84 which bears at its lower end upon the top circumferential margin of the adjusting wheel 34, and at its upper end is normally slightly spaced from the frame 15 of the tubular switch element 1|. The frame 15 is preferably provided with an upwardly extending arm 85 with a terminal knob 86 for easy manual actuation.

It is believed the operation of the apparatus will be readily understood from the description of its construction, but a brief summary will be made to show the complete adjustment and operation of the apparatus as applied to the elements shown inFig. 1.

The heating current is started in the upper and lower platens and the temperature checked. The

shaft is reversed through the hand wheel to lower the platen or movable abutment l to the requisite extent, and the tubular spacing and pressure distributing member I8 i then engaged between the top 'plate 14 and the upper movable abut-- tomary to use metal foil lining for the mold cavity. This must not be broken or disturbed during the period of application of heat and pressure to the plate material in the mold cavity.

A careful adjustment of the flask between the I platens or movable abutments is then made, and.

1. An apparatus of the character described comprising, a base member, a frame rigidly secured thereto, a fixed abutment on said frame, a movable abutment on said frame, means for moving said movable abutment toward said fixed abutment, said means including a movable member and a frame-contacting, sliding, abutment locking and releasing element on said movable member, and means actuated by said movable member for stopping said abutment moving means after said abutment has reached its limit of closing movement.

2. An apparatus of the character described having in combination a frame providing a support, a fixed abutment and a movable abutment on said support, a plurality of movable elements for moving saidmovable abutment toward said fixed abutment including a lost-motion connecanism to elevate the lower platen or movable abutment. The low gear ratio brings about a very gradual closing of the flask and the platens locking of th driving mechanism. The-com pressible spring and its associated elements fully take care of either of these contingencies, as the mechanismis not stopped until the closing point is well passed. As the flask sections are brought into firmly closed relation, the spring 3| must take up the thrust of the shaft 28 and as the spring is compressed, the adjusting wheel rim forces the pin 84 upwardly tilting the tubular switch element I l to bring the mercury globule to the non-circuit closing position shown in Figure 3. When the operation is thus terminated, the flask, or other element, may be readily removed by withdrawing the locking bar 39 from it's socket and reversing the rotation of the adjusting wheel 34. The pinion 41 engaging the disk extension 46 prevents-the collar 4| from turning and thus the shaft 28 may be turned down and adjusted to proper starting position. Thereafter the cycle may be repeated as outlined.

Other modes of applying the principle of our invention may be employed instead of those explained, change being made as regards the mechanism herein disclosed, provided the means stated tion having a spring element between said movable elements and said movable abutment, and a frame-contacting, sliding, abutment locking and releasing element on one of said movable elemerits, whereby the movement of at least one of said elements will be continued after the movable abutment has reached its limit of movement toward the fixed abutment.

3. An apparatus of the character described having in combination a frame providing a support, a fixed abutment and a movable abutment, a screw-threaded shaft supported for axial movement adjacent said movable abutment, a removable frame-contacting pin associated with said shaft and forming a sliding guide for restraining the rotation of said shaft, a rotatable screw-threaded element engaging the threads of said shaft to move said shaft and movable abutment toward said fixed abutment, and resilient means bearing frictionally on said shaft whereby manual rotation of said shaft releases said movable abutment, after the removal of the pin.

4. An apparatus of the character described 7 having in combination a frame providing a support, a fixed abutment and a movable abutment, a screw-threaded shaft supported for axial movement adjacent said movable abutment, a hand wheel secured to said shaft, a removable framecontacting guide pin for said hand wheel to prevent rotation of said shaft, means engaging said shaft for advancing the same axially to move the movable abutment toward said fixed abutment, and resilient means bearing frictionally on said shaft, whereby manual rotation of said shaft by said hand wheel releases said movable abutment, after the removal of the pin.

5. An apparatus of the character described having in combination a frame providing a support, a fixed abutment and a movable abutment, a screw-threaded shaft supported for axial movement adjacent said movable abutment, a fixed guide member internally of said shaft, a hand wheel secured to said shaft, a removable frame-contacting guide pin for said hand wheel to prevent rotation of said shaft, means engaging said shaft for advancing the same axially to move the movable abutment, and resilient means bearing frictionally on said shaft, whereby manual rotation of said shaft by said hand wheel releases said movable abutment, after the removal of the pin.

GARLAND S. VARCOE. EDWIN A. PURDY. 

